Here's my observation of NGC 1647 with the unaided eye. We do live in a semi-arid area, the southern Okanagan Valley of British Columbia, but my backyard is not on a mountain; it is on the valley floor beside Skaha Lake in a subdivision that 40 years ago voted against the light pollution of streetlights in a referendum. I was 63 years old at the time, and it was four years before I had cataract surgery so my naked-eye acuity was not as good as it is now. Penticton city limits (a city of 32,000) are only 6 km North of me.
September 22, 2009
On this first morning of autumn I went out in bed clothes to check the sky, intending to be out only for a moment, but was greeted with a superb sky and spent 30 entrancing minutes, from 0350 to 0420 PDT in 7 degree Celcius, wearing only a T-shirt, socks, sandals, and a dressing gown. After hours of dark adaption in bed M33 and M35 were both vary obvious naked-eye objects, so I tried the three Messier open clusters in Auriga. All three were seen with the unaided eye, and confirmed with my 7x50 binoculars. This was only the second time that I had seen M36, M37, and M38 with the unaided eye.
Then I added two new objects to my list of naked-eye open clusters, NGCs 1647 and 1746 in Taurus. Both of these large clusters were confirmed with binoculars. These were the 40th and 41st open clusters that I have spotted with the unaided eye (including some clusters from Australia).
If the sky was this good, what about the zodiacal band? Sure enough, the zodiacal band was visible on the ecliptic across western Taurus, Aries, and Pisces through to the Gegenschein which, surprisingly, was still visible even though it was more then three hours after local midnight.
Those overly pessimistic light pollution charts claim that I live in the green zone!